Public telephones, such as public payphones, have become increasingly obsolete due to advances in technology and the proliferation of numerous telephony options for customers. Because public telephones are stationary, but were generally built prior to development of many existing technologies, operators have not been able to take advantage of potential cost savings. For example, most public telephones still in existence are connected via landlines of local telephone exchanges, and use power delivered by the electrical grid operated by the local utility.